liteeth: only raise CRC errors on CRC mismatch at end of packet.

whitequark · whitequark · commit 72faa2c7fc17 · 2017-10-30T09:27:35.000Z
Otherwise every packet implies a CRC error.
diff --git a/misoc/cores/liteeth_mini/mac/crc.py b/misoc/cores/liteeth_mini/mac/crc.py
@@ -257,13 +257,9 @@ def __init__(self, crc_class, layout):
             source.payload.eq(fifo.source.payload),
 
             source.error.eq(sink.error | crc.error),
+            self.crc_error.eq(sink.eop & crc.error),
         ]
 
-        crc_error_r = Signal()
-
-        self.comb += self.crc_error.eq(crc.error & ~crc_error_r)
-        self.sync += crc_error_r.eq(crc.error)
-
         fsm.act("RESET",
             crc.reset.eq(1),
             fifo.reset.eq(1),
